An electrophile is an electron pair acceptor. It is electron deficient and can accept a pair of electrons to form a new dative covalent bond.Electrophiles are positive ions, such as H+ and NO2+, or molecules with a δ+ atom, such as the hydrogen in H-Br.Electrophiles attack regions of high electron density. The π bond in an alkene and the delocalised ring of benzene are both attacked by electrophiles.A non-polar molecule such as Br2 can act as an electrophile when the electron-rich C=C bond polarises it, making one bromine atom δ+. This happens in electrophilic addition.